Re: Concurrency in Gnat 3.05?

[mfeldman@seas.gwu.edu (Michael Feldman)]

In article <JSA.96Jul19133310@alexandria>,
Jon S Anthony <jsa@alexandria> wrote:

>The point is that time slicing behavior is system dependent.  

And THAT was the import of Robert Dewar's posts on this subject.
The only way to even approach system-_indepencdent_ behavior
is to assume no time-slicing. That is just as well, IMHO -
it's best to write programs whose behavior you understand, 
not programs whose behavior depends upon an unpredictable
time-slicing scheme in the OS.

That is _easier_ to do with Ada tasking.

>Actually, that brings up another point.  Since you have Win95
>why are you running the DOS version of GNAT under a DOS window instead
>of just using the native Win95?

But it should not matter; the point is the same. Indeed, one's
multitasking program ought to behave in the same way - on an input/
output basis - with or without time-slicing. If it does not, it is
a poorly designed concurrent program.

That program of mine, cited by the original poster, is introduced
in the chapters on concurrency in my texts.  Precisely the point
of that program - as the text explains - is that its behavior
_does_ depend on the presence or absence of time-slicing, and the 
ensuing examples show how to remove the dependency!

Newly updated program distributions are available at 
ftp://ftp.gwu.edu/pub/ada/courses. These distributions contain
an index of the programs in the order they appear in the text,
so you can study them in the proper sequence.

[BLATANT PLUG]
Better to buy the books, of course.:-)

Home pages for the books are at 

http://www.aw.com/cseng/authors/feldman/cs1-ada2e/cs1-ada2e.html
(Ada 95 Problem Solving and Program Design)

http://www.aw.com/cseng/authors/feldman/cs2-ada/cs2-ada.html
(Software Construction and Data Structures with Ada 95)

Both books are available now.

Mike Feldman